An increased consumption of fruit and vegetables has been
associated with beneficial effects on the risk of disease (1–5).
Citrus juices, especially orange juice and grapefruit juice, are
rich sources of vitamin C, but their health benefits remain
poorly understood. Recent reports suggested that drinking generous
amounts of a mixture of various juices improves the blood lipid profile, reduces oxidative stress, prevents atherogenic
modifications of LDL cholesterol and platelet aggregation
(6–8), and improves HDL-cholesterol concentrations (9). Several
studies have shown that vitamin C plays an important role
in human health, including effects on the immune system (10),
the risk of Alzheimer disease (11), and the efficiency with
which lysosomes in brain glial cells degrade modified proteins
(12). However, no study has examined the bioavailability of
vitamin C in orange juice and its possible beneficial effects on
reducing isoprostane concentrations.
Isoprostanes are a family of eicosanoids of nonenzymatic origin
that are produced by the random oxidation of phospholipids by
oxygen radicals and that are elevated by oxidative stress (13, 14).
One of the isoprostanes, 8-epi-prostaglandin F2 (8-epi-PGF2),
has been shown to act as a vasoconstrictor (15) and to be associated
with the hepatorenal syndrome and pulmonary oxygen toxicity
(16). Previous studies showed decreased concentrations of
antioxidants and high concentrations of 8-isoprostanes among
smokers (17, 18), which may be due to a low intake of antioxidants
(19) or a greater utilization of vitamin C by free radicals
produced during smoking (20).
High serum uric acid may be an important predicting risk factor
for cardiovascular events, such as myocardial infarction (21).
Multivariate analysis of data from the MONICA cohort of 1044
An increased consumption of fruit and vegetables has beenassociated with beneficial effects on the risk of disease (1–5).Citrus juices, especially orange juice and grapefruit juice, arerich sources of vitamin C, but their health benefits remainpoorly understood. Recent reports suggested that drinking generousamounts of a mixture of various juices improves the blood lipid profile, reduces oxidative stress, prevents atherogenicmodifications of LDL cholesterol and platelet aggregation(6–8), and improves HDL-cholesterol concentrations (9). Severalstudies have shown that vitamin C plays an important rolein human health, including effects on the immune system (10),the risk of Alzheimer disease (11), and the efficiency withwhich lysosomes in brain glial cells degrade modified proteins(12). However, no study has examined the bioavailability ofvitamin C in orange juice and its possible beneficial effects onreducing isoprostane concentrations.Isoprostanes are a family of eicosanoids of nonenzymatic originthat are produced by the random oxidation of phospholipids byoxygen radicals and that are elevated by oxidative stress (13, 14).One of the isoprostanes, 8-epi-prostaglandin F2 (8-epi-PGF2),has been shown to act as a vasoconstrictor (15) and to be associatedwith the hepatorenal syndrome and pulmonary oxygen toxicity(16). Previous studies showed decreased concentrations ofantioxidants and high concentrations of 8-isoprostanes amongsmokers (17, 18), which may be due to a low intake of antioxidants(19) or a greater utilization of vitamin C by free radicalsproduced during smoking (20).High serum uric acid may be an important predicting risk factorfor cardiovascular events, such as myocardial infarction (21).Multivariate analysis of data from the MONICA cohort of 1044
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